Microorganisms in an aquatic environment have a marked tendency to grow on submerged surfaces, such as vessels or pipes carrying a flow of natural water. The microorganisms which colonize the surface secrete a surrounding structure called a glycocalyx which is usually composed of polysaccharides. The matrix structure formed by the microorganisms and the glycocalyx is generally referred to as a biofilm. The biofilm structure allows the microorganisms inhabiting the biofilm to remain viable during periods of environmental stress such as inadequate food, adverse temperature, drying or the presence of deleterious chemicals. In the operation of vessels or conduits carrying water such as heat exchangers, biofilms can substantially increase the resistance to fluid flow, reduce the heat transfer capacity and lead to increased corrosion of metal surfaces.
Efforts to control or eliminate biofilms have not been particularly successful. Biocides have difficulty in penetrating the glycocalyx formed by the microbes, thereby necessitating the use of a large quantity of these compounds to control biofilms. Mechanical abrasion has also been tried by passing "pigs", abrasive balls or ice crystals over the surface to dislodge biofilms. None of these methods have been particularly successful and tend to be labor intensive and expensive.
Thus it would be a significant contribution to the art to develop a simple, inexpensive, and effective process of removing biofilms from submerged surfaces.
It is thus an object of this invention to provide a simple, inexpensive, and effective process for the removal of biofilms from submerged surfaces.
Other objects, aspects, and advantages of the present invention will be apparent to those skilled in the art from the following description, examples and claims.